This one offers almost nothing to the naked eye: a faint rise in a field, perhaps thirty metres across, that most walkers would step over without a second thought. What gives it away, if anything does, is the subtlest suggestion of a ditch around its edge, and even that is largely gone. The enclosure at Ballysimon sits on low-lying pasture roughly sixty metres east of the Groody River, and its most legible form exists not on the ground at all but from the air, where it appears as a suboval cropmark on satellite imagery.

Cropmarks form when buried features, old ditches, filled pits, or buried walls, affect how crops or grass grow above them, revealing outlines invisible at ground level. The Ballysimon enclosure was noted in 2003 by Collins, who described it as a slightly raised area defined by traces of a ditch, and it subsequently appeared clearly on Digital Globe orthophotos taken between 2011 and 2013, and again on a Google Earth image from February 2018. What the site was originally used for remains unresolved. Enclosures of this general character in Ireland range from early medieval farmsteads, known as raths or ring-forts, to later agricultural features, though without excavation or dating evidence, any attribution here would be speculation. Notably, it does not appear on the Ordnance Survey's historic mapping, which suggests either that it had already largely disappeared by the nineteenth century or that it was never sufficiently visible to be recorded by surveyors. A working watermill, the Ballysimon watermill, stood around eighty metres to the north, and the proximity of both features to the Groody River points to the kind of layered, practical land use that characterises many Irish river margins over centuries.

The site lies on private agricultural land, and there is nothing to see from a public road that would reward a dedicated visit in the conventional sense. Its interest is primarily in what it represents: an ordinary-looking field that holds the ghost of an old boundary, legible only to those with access to aerial imagery or a particular reason to look closely. Anyone curious to examine the cropmark evidence can do so through Google Earth, using the coordinates near Ballysimon, south-east of Limerick city. The February 2018 image, compiled as part of the record by Alison McQueen and Vera Rahilly, offers the clearest view currently available.